Presently, owing to the boost of oil price and the influence of the greenhouse effect, the green energy industry is valued highly and developing prosperously. In recent years, solar cell technologies progress continuously. Currently, silicon solar cells, thin-film solar cells, and concentrating solar cells are the mainstreams in the market. The concentrating solar cells adopt concentrating lenses to concentrate solar energy, in the hope of still gaining better optoelectronic conversion efficiency than traditional single-crystalline, polysilicon, and thin-film solar cells even the number of chips is reduced.
A general concentrating solar-cell module is mainly formed by concentrating lenses, solar cells, secondary optical devices, a circuit board, and a module frame. The combination of the solar cells, the circuit board, and the secondary optical devices is called a package board. Because the operating principle of a concentrating solar-cell module is to concentrate the sunlight to small-area solar cells for generating power, the accuracy of packaging location of solar cells and the precision of forming secondary optical devices are extremely crucial to the performance of power generation.
In general inspection, the optical visual inspection equipment is adopted for taking pictures before image analysis. Unfortunately, in addition to solar cells, there are secondary optical devices on the package board, making the images formed by the optical visual inspection equipment defocused or deformed. Consequently, it is difficult to perform inspection.
In addition, for the optical visual inspection equipment according to the prior art, digital images of the devices under inspection are taken using a camera disposed above before analysis. There can be flaws in the package boards of a concentrating solar cell, including horizontal shifts of solar cells and micro bubbles in the secondary optical devices located at different depths. Limited by the focusing depth of a camera lens, it is not possible to judge the above flaws in the same image. Furthermore, the refraction of light by the secondary optical devices deforms the images, making the inspection using the optical visual inspection equipment more difficult.
Accordingly, in the method for inspecting solar cell packages according to the prior art, there remains many faultful structures. After long-term researches and innovation, the present invention provides a method for inspecting solar cell packages. According to the method, a power supply applies a forward bias to solar cells, which then emit light owing to the electroluminescence phenomenon. The light passes through the secondary optical devices on the solar cells and is received by the photosensors above the solar cells. The photosensors move above the solar cells along various angles for acquiring the distribution of light intensity of the solar cells with respect to angles. Next, computer or analysis software is used for judging if the precision of the solar cell package and the secondary optical devices are defective.